Information sharing and exchange between application tools used in the construction industry are long-term objects of relevant researchers. To this end, Industry Foundation Classes (IFC), which is a standard data model, has been developed by Building Smart International and applied to practical applications. Building objects are defined by Building Information Modeling (BIM) to represent the real world in a virtual CAD environment, and BIM objects are converted into IFC object model instances. Consequently, BIM, which is based on IFC, may be defined as a new concept for exchanging BIM data between BIM platforms.
During the process of construction design, there may be multiple changes to an initial plan over time. Whenever any change occurs, the IFC file may be separately saved, and the saved IFC file may become a different version of the IFC file. The different versions of the IFC files may be visually displayed through software such as Autodesk Revit, ArchiCAD, Digital Project, and the like.
Meanwhile, when there are different versions of IFC files, it is necessary to detect or control the changes in the IFC files. For the different versions of IFC files, conventional methods control the changes by indicating the versions in file names or by writing memos in the files used with Autodesk Revit, ArchiCAD, Digital Project, and the like. When the versions are expressed in the file names, it is impossible to detect and compare information about the changes beyond the change in the version or the text information included in the file name. Also, when a user of an authoring tool, such as Autodesk Revit, ArchiCAD, Digital Project, and the like, writes details about changes, such details may be omitted. Particularly, when multiple users collaborate using such tools, there is a high probability of omissions and mistakes (including miscommunication) in tracking the changes. Also, when the changes occur over multiple objects, it is difficult to directly extract, compare, and control the changes for each of the IFC versions. Furthermore, because the size of the IFC file is very large (the size ranges from dozens of megabytes to gigabytes and beyond) and the structure thereof is very complicated, visually tracking the changes in the IFC files is almost impossible.
On the other hand, IFC has an enormous number of objects. Accordingly, when changes are tracked based on each of the objects, extracting and comparing the changes for each of the IFC versions is very difficult and inefficient due to the IFC file size and the number of objects. Also, even if the object information (including the object attribute information) included in the IFC files is stored in a DB, version comparison targeting all the objects may cause a decline in both efficiency and speed due to the problem of a huge number of objects.